The first thing you notice about Koo Stark is her hair. She wears it in exactly the same style as she did at the height of her fame 25 years ago, when as a ravishing young American actress she captured the heart of Prince Andrew and came tantalisingly close to becoming his Princess.

It is long, heavy, swingy, lustrous and dark, although streaked with grey these days, and she tosses it over her shoulder in luxurious sweeping gestures in a rather glamorous manner reminiscent of shampoo commercials.

In 2002, after she underwent a mastectomy after being diagnosed with second stage breast cancer, all her hair fell out during the subsequent course of chemotherapy.

She grieved the loss of that more than her breast because to her it was the outward symbol of her femininity.

Then and now: The former beauty at the height of her fame, and as she is today

When it started to grow back, she was shocked to see so much grey and little swirling cowlicks everywhere, making her hair stick up like a schoolboy's.

'When my hair grew back, it was so different from how it was before that I thought maybe I should dye it,' says Koo, 52.

'I thought mid-to-light brown would be nice, but when I dyed my hair it was like brass.

'With all the cowlicks, I looked as if I had been plugged into an electric socket. I went to see Neil at the Long Hair Clinic in London, who's been looking after my hair for 25 years, and he sighed, shook his head and said: "Well, you won't be doing that again, will you?"

'He said the only thing to do was to keep growing it, which is what I did, and it's back to how I remember it - except for the colour.

'I have thought about dying it dark again, but that is a huge, long-term commitment using very toxic dye and the costs would be exorbitant.'

Life has not been kind to Koo. Her romance with the Queen's favourite son in the early Eighties became one of the most memorable royal love stories.

She was besotted with him, but the relationship was scuppered by disapproving palace courtiers aghast at revelations she'd once appeared naked in a mildly erotic film in the Seventies.

Her recent experiences are a sharp reminder that being a celebrity is not always the glamorous existence people think it is. For her, it has often felt like a burden, and she is one of the few who is honest enough to admit it.

She managed to rebuild her life following the Prince Andrew episode and 12 years ago things seemed good.

She was the Prince's ex-turned successful photographer with £1million in the bank and a wealthy banker fiance.

As a young actress, Koo captured the heart of Prince Andrew 25 years ago

But today she is a struggling single mother, trying to bring up 11-year-old daughter Tatiana while fighting her way back to health and on the brink of bankruptcy with debts of £200,000.

Where once her doormat was littered with invitations to glitzy parties in heavy, expensive-looking envelopes, she now dreads the arrival of another brown envelope with a bill inside.

She files them, unopened, in a heap under her sofa because she has no way of paying them. Koo has had to resort to hiding from bailiffs, refusing to open the door - her money having been eaten up in lawyers' fees following the acrimonious collapse of her relationship with Tatiana's father.

He was American banker Warren Walker, who reportedly called off their wedding ten days before the ceremony, when Koo was seven-and-a-half months pregnant.

With the dispute between them on-going, Koo refuses to talk about this, but it is well-documented that he launched a custody application.

In 2000, Koo responded by suing the multi-millionaire for punitive damages for emotional distress and failure to provide for his child, after allegedly discovering he had become engaged to a former girlfriend at the same time he was betrothed to her.

So dire is her financial situation that Koo had to leave hospital less than six hours after her mastectomy in the U.S. because she could not afford the fees.

She claims she had to go abroad for treatment because British doctors misdiagnosed her illness.

She had a second preventative mastectomy the following year, terrified the cancer might return.

Last year, she considered taking part in I'm A Celebrity . . . Get Me Out Of Here! and Dancing On Ice, purely for the fees.

Both projects bit the dust for reasons she won't discuss, but a fair guess would be that her health was involved.

'I've never had a business brain. I am a creative person. When you have money it means nothing to you, but when you don't have any it affects every aspect of your life. I have to think about the cost of everything,' she says.

Koo Stark, pictured in her prime, lying semi-naked on a bed in a scene from the erotic coming-of-age film Emily

I met Koo a couple of days after pictures appeared of her walking her poodle near her home in Knightsbridge, looking as if she had the world on her shoulders.

In the photos, the gorgeous mane of hair looks strangely at odds with the unmade-up face, shapeless black T-shirt, trousers and boots. Certainly it is a dramatic contrast to Koo the Eighties bombshell.

She admits she was mortified by the photographs. Not because she is a vain woman - she most definitely isn't - but because the past few years have been a trial and it was hard to see that reflected back at her.

'It is difficult to age because society won't let you. People expect you to look how you did at the height of your fame.

'There are celebrities who try to maintain that look - Joan Collins still looks like the Joan Collins we all know and love.

'If any of my fans would like to pay to return me to the way I was when I was 25, I'd love to hear from them because I don't have the money for all those extraordinary cosmetic procedures.

'Even when I was in my 20s and at my most beautiful, I was never obsessed with my looks. I didn't dye my hair or wear make-up.

'I was entirely natural and in many ways I have the same attitude now. I don't mourn the loss of my youth because I believe you should enjoy what you have while you have it.

'But today, when I look in the mirror, I'm not happy with my looks, not because I am getting older, but because they are an indication of my health.

'I haven't recovered completely from the chemotherapy, which is very toxic and leaves you looking bloated.

'I don't regret having it because I'm a mother, and to me it was important to do everything to ensure my survival, but if I had been a childless woman I would have thought very hard about having chemo.

'Obviously, having lost both my breasts, my shape has changed completely and sometimes I feel awkward in clothes.

'Manufacturers don't make clothes for women with no breasts. My skin is very sensitive and I suffer from psoriasis.

'When you don't feel well and can't see that inner glow any more you reach a point when you think: "Yes, I will have that ice cream." If I can't have anything else then at least I can enjoy my food.'

Koo adds: 'True beauty to me is not about outward appearances. You can't buy it and slip-slap it on.

'It emanates from health and is reflected in the benefit of healthy hair and skin, a positive mental attitude and emotional completeness. To coin a phrase, it's about having a good vibration, and I don't have that.

'When I had my breasts removed, I turned down the option of having reconstruction straight away, because implants can cause scar tissue which can mask cancer cells on scans, but I have been clear of the disease for five years, so it is something I might consider.

'My daughter is at an age when she is becoming more aware of body image. It can be limiting not being able to go swimming because I feel awkward in a bathing suit.

'I would love to be able to afford a personal trainer, doctor, dentist and accountant to go through all those brown envelopes so I can pay back my debts, but I just can't.'

Koo's career as a photographer has suffered because she can no longer afford a studio or assistants. She still takes photographs, but it takes longer to put an exhibition together.

Yet she displays a Zen-like calm, which she puts down to her Buddhist faith. She says she has no attachment to money or material possessions and what really matters to her is being a good mother to Tatiana.

'I'm not very interested in buying designer clothes or going out to parties,' says Koo.

'I remember when just before my mother died in 2005, she said the most important thing people can take with them is happy memories, so that's I what I want to give Tatiana, and those are free.'

As a self-employed artist, Koo's income is sporadic and dependent on her health and time.

'I consider myself to be a lucky woman. One in eight women suffers from breast cancer and some don't make it - last August, when I celebrated five years of being clear of this disease, I said a prayer for those who hadn't.

Known for her beauty which led to her first major role, it seems that age has caught up with Koo from head to toe

'The only time Koo's serenity wavers and fire flashes into her startlingly blue eyes is at the mention of Prince Andrew.

They remain friends, he is Tatiana's godfather and she is wary of saying anything that might upset him or be construed as indiscreet.

Indeed, she appears mystified as to why interest in her remains strangely undimmed a quarter of a century after their romance ended, and says the experience of being chased by 60 paparazzi back then has left her craving anonymity.

Why, then, in 1986, did she marry handsome Tim Jefferies, the gallery owner most commonly referred to as the Green Shield Stamps heir and a permanent fixture in the society pages?

'When I married Tim he was the manager of a hi-fi shop in East Grinstead and lived in a red-brick Barratt house,' says Koo of her brief marriage, which ended in divorce in 1990.

'He wasn't rich or famous then and I thought I'd disappear to West Sussex and live quietly as Mrs Jefferies.'

Alas, it was not to be. Indeed, every time Tim Jefferies's name crops up - this year he married Swedish model Malin Johansson, and has been linked with a string of beauties including Elle Macpherson - Koo gets a mention as his ex.

She will never be anonymous, but ask her if she regrets her involvement with the Prince, and she dismisses the question.

They were set up by mutual friends on a blind date when Koo was appearing in Who's Afraid Of Virginia Woolf? at the National Theatre and Andrew was in the Navy.

They hit it off immediately and she became a regular visitor at Buckingham Palace, where she got on famously with the Queen.

But the romance reportedly flourished while it was still secret and was serious enough for them to talk of children.

All hell broke loose, however, when they went on holiday together to the Caribbean island of Mustique, after the Falklands War, and a photographer spotted them at the airport.

The paparazzi descended, and Koo, the daughter of an American TV presenter, found herself the subject of scrutiny, not least when it emerged she'd appeared in a film called Emily which, although tame by today's standards, caused a scandal at the time. It was the first time a serious royal girlfriend had been chosen from outside 'the Firm's' usual aristocratic circle and it caused a furore.

Her American nationality worked against her, with some palace insiders saying they didn't want another Wallis Simpson.

Andrew was re-branded the Playboy Prince and Koo was dubbed the 'soft porn actress', a label which still causes her to shudder.

'Nothing can prepare you for that level of interest in your private life,' says Koo, who in the Eighties famously turned down an offer of £1million to talk about her romance.

'I made the mistake of thinking that if I didn't talk about it, it would go away. When you lose your reputation, you lose it for ever, even if what is said about you isn't true. Seven years later I successfully sued for libel.'

Today, Koo's romance with Andrew is a closed book, but she values him as a friend.

'Everyone who touches your life is important to you and whether you view that experience as positive or negative is down to you.

'You choose whether to come out of a relationship bitter or not, and I choose not to.

'The only thing you have control over in your life is your reaction; you can't control other people. It's not going to make you feel better to wallow in self-pity - you have to get up and get on. Being angry is like picking up a knife with no handle: it is self-harming.'

But surely she must wonder sometimes how her life might have turned out if her romance with Prince Andrew had led to a fairytale ending.

'I've had the good fortune to have been indulged in the past, but people have this false perception that life is different for famous people. I have the same problems as everyone else and I hope that by talking about them, I will inspire other women.'

And with a final toss of that long mane of hair, she leaves to pick up her daughter from school.